NEW YORK -- Bell Atlantic Corp., racing to boost its ability to offer high-speed data-transmission services, said it plans to build an advanced, long-distance data network, even though it doesn't yet have permission to offer long-distance voice and data services in its 13-state region.

The project, which is expected to cost roughly $500 million over the next five years, comes as telephone carriers are grappling with ways to handle the huge growth in data traffic fueled by the Internet. Bell Atlantic said the plan, which...